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I was part of a discussion about the differences between all engine climb gradients and OEIone engine inoperative (OEI) climb gradients, and a colleague suggested that climb gradient can be calculated as

$$G = \frac{T-D}{W}$$

Where

• $$G$$ is Climb Gradient as a percent,
• $$T$$ is Thrust,
• $$D$$ is Drag, and
• $$W$$ is Weight.

This derivation was never really explained, and it doesn't really make sense to me. He continues by stating that lift can be assumed to equal weight for small climb angles, so that his equation becomes

$$G = \frac{T}{W} -\frac{D}{L}$$

Where $$L$$ is Lift.

For some analyses, I can see using the approximation $$W = L$$, but since that is essentially assuming your climb gradient is 0, it doesn't seem prudent to use that assumption to calculate the climb gradient itself.

Has anyone seen these equations before? Or is there a piece to this that I'm missing that someone could explain to me?

I was part of a discussion about the differences between all engine climb gradients and OEI climb gradients, and a colleague suggested that climb gradient can be calculated as

$$G = \frac{T-D}{W}$$

Where

• $$G$$ is Climb Gradient as a percent,
• $$T$$ is Thrust,
• $$D$$ is Drag, and
• $$W$$ is Weight.

This derivation was never really explained, and it doesn't really make sense to me. He continues by stating that lift can be assumed to equal weight for small climb angles, so that his equation becomes

$$G = \frac{T}{W} -\frac{D}{L}$$

Where $$L$$ is Lift.

For some analyses, I can see using the approximation $$W = L$$, but since that is essentially assuming your climb gradient is 0, it doesn't seem prudent to use that assumption to calculate the climb gradient itself.

Has anyone seen these equations before? Or is there a piece to this that I'm missing that someone could explain to me?

# How is the climb gradient calculated?

I was part of a discussion about the differences between all engine climb gradients and one engine inoperative (OEI) climb gradients, and a colleague suggested that climb gradient can be calculated as

$$G = \frac{T-D}{W}$$

Where

• $$G$$ is Climb Gradient as a percent,
• $$T$$ is Thrust,
• $$D$$ is Drag, and
• $$W$$ is Weight.

This derivation was never really explained, and it doesn't really make sense to me. He continues by stating that lift can be assumed to equal weight for small climb angles, so that his equation becomes

$$G = \frac{T}{W} -\frac{D}{L}$$

Where $$L$$ is Lift.

For some analyses, I can see using the approximation $$W = L$$, but since that is essentially assuming your climb gradient is 0, it doesn't seem prudent to use that assumption to calculate the climb gradient itself.

Has anyone seen these equations before? Or is there a piece to this that I'm missing that someone could explain to me?

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I was part of a discussion about the differences between all engine climb gradients and OEI climb gradients, and a colleague suggested that climb gradient can be calculated as

G = (T-D)/W$$G = \frac{T-D}{W}$$

Where

G is Climb Gradient as a percent, T is Thrust, D is Drag, and W is Weight.

• $$G$$ is Climb Gradient as a percent,
• $$T$$ is Thrust,
• $$D$$ is Drag, and
• $$W$$ is Weight.

This derivation was never really explained, and it doesn't really make sense to me. He continues by stating that lift can be assumed to equal weight for small climb angles, so that his equation becomes

G = (T/W) - (D/L)$$G = \frac{T}{W} -\frac{D}{L}$$

Where L$$L$$ is Lift.

For some analyses, I can see using the approximation W = L$$W = L$$, but since that is essentially assuming your climb gradient is 0, it doesn't seem prudent to use that assumption to calculate the climb gradient itself.

Has anyone seen these equations before? Or is there a piece to this that I'm missing that someone could explain to me?

I was part of a discussion about the differences between all engine climb gradients and OEI climb gradients, and a colleague suggested that climb gradient can be calculated as

G = (T-D)/W

Where

G is Climb Gradient as a percent, T is Thrust, D is Drag, and W is Weight.

This derivation was never really explained, and it doesn't really make sense to me. He continues by stating that lift can be assumed to equal weight for small climb angles, so that his equation becomes

G = (T/W) - (D/L)

Where L is Lift.

For some analyses, I can see using the approximation W = L, but since that is essentially assuming your climb gradient is 0, it doesn't seem prudent to use that assumption to calculate the climb gradient itself.

Has anyone seen these equations before? Or is there a piece to this that I'm missing that someone could explain to me?

I was part of a discussion about the differences between all engine climb gradients and OEI climb gradients, and a colleague suggested that climb gradient can be calculated as

$$G = \frac{T-D}{W}$$

Where

• $$G$$ is Climb Gradient as a percent,
• $$T$$ is Thrust,
• $$D$$ is Drag, and
• $$W$$ is Weight.

This derivation was never really explained, and it doesn't really make sense to me. He continues by stating that lift can be assumed to equal weight for small climb angles, so that his equation becomes

$$G = \frac{T}{W} -\frac{D}{L}$$

Where $$L$$ is Lift.

For some analyses, I can see using the approximation $$W = L$$, but since that is essentially assuming your climb gradient is 0, it doesn't seem prudent to use that assumption to calculate the climb gradient itself.

Has anyone seen these equations before? Or is there a piece to this that I'm missing that someone could explain to me?

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